The biggest problem is that he's seen how pleased Nate is to have the new responsibility, and how well he's responding to the position. If Anders says what's on his mind, he might taint the one good thing that's happened to Nathaniel in a very long time. He's caught between wanting to gripe and not wanting to hurt Nate and he doesn't like it.

"Nothing." A beat. "All right, yes, something, I just... It's complicated."

He's never not told Nate something before. He can't see this going that well, but he doesn't know what else to say and he can't wave his staff and magically fix his mood.